Fire, Land Use and the Savannazation of Seasonally-dry Amazon Forests

每年，全世界人类活动排放到大气中的二氧化碳总量中，约有五分之一来自砍伐和焚烧潮湿的热带森林。 在严重干旱的年份，大面积的森林着火，使这些排放量增加一倍。 森林一旦被烧毁，就更有可能再次燃烧，形成森林退化的恶性循环，进一步增加大气中的碳排放，因为它破坏了热带雨林。 这项研究将揭示决定森林对火灾的反应的过程，以及亚马逊大规模“稀树草原化”的可能性-热带雨林转变为易发生火灾的灌木植被。 它将通过实地实验和对被烧毁森林的测量来实现这一目标，这些实验和测量确定亚马逊森林火灾对随后易燃杂草入侵和树木死亡的影响-这两个因素强烈影响进一步燃烧的风险。 获得的数据将用于修改亚马逊植被模型，该模型将用于预测大规模草原化的可能性及其对大气的潜在碳贡献。 目前，预测热带森林在变暖世界中的未来的模型不包括火灾，杂草入侵和土地使用。这项研究将填补亚马逊热带森林如何应对气候变化和热带森林日益增长的经济压力的知识空白。 该项目还将支持国际教育、学生交流和旨在普及环境知识的公共宣传活动。

Each year, about one fifth of all of the carbon dioxide that is emitted to the atmosphere through human activities around the world comes from the clearing and burning of moist tropical forests. During years of severe drought, large areas of forest catch fire, doubling these emissions. Once burned, forests are more likely to burn again in a vicious cycle of forest degradation that further increases carbon emissions to the atmosphere as it damages rainforests. This research will shed light on the processes that determine the response of forests to fire, and the likelihood of large-scale "savannization" of the Amazon - the transformation of rainforest into fire-prone brush vegetation. It will achieve this through field experiments and measurements of burned forests that determine the effects of Amazon forest fire on subsequent invasion by flammable weeds and tree death - two factors that strongly influence the risk of further burning. The data obtained will be used to modify a vegetation model of the Amazon that will be used to predict the likelihood of large-scale savannization and its potential contribution of carbon to the atmosphere. Currently, models that predict the future of tropical forests in a warming world do not include fire, weed invasion, and land use.This research will fill an important gap in knowledge of how tropical forests in the Amazon will respond to climate change and growing economic pressures on tropical forests. This project also will support international education student exchanges and public-outreach activities aimed at environmental literacy.